The present invention pertains to air filtration devices, and more particularly to efficient and quiet air filtration devices designed to be mounted on a ceiling.
Indoor pollutants, including airborne pollutants such as dust, pollen, and cigarette smoke are potentially as harmful to health. Enclosed areas also concentrate other indoor pollutants such as formaldehyde and bacteria, especially in new buildings without operable windows. Thus, there is a demand for methods of and mechanical devices for removing indoor air pollutants. Devices used to remove airborne pollutants fall into two categories: devices integrated into a building""s air handling system, and devices that are free standing. Each of these has several disadvantages: air filtration systems that are integrated with a building air handling system are efficient, but are very expensive and, if not incorporated at construction time, retrofit is costly in labor and materials if it is even possible. Free-standing devices are cheaper and can be added in a room after construction, but are bulky, take up a lot of room, and cannot be conveniently centrally located. Moreover, they are not designed to be simply hung in a space and switched on.
Some attempts have been made to design a device which incorporates the convenience and lower cost of free-standing devices with the unobtrusiveness of an integrated system. One such attempt is shown in U.S. Pat. No. 4,849,862 to Diskin et al. Diskin discloses a ceiling-mounted air purification unit. This purification unit has several disadvantages. First, the Diskin device is still quite bulky and takes up a significant amount of space. Second, its construction makes it expensive and difficult to build, because of the type, amount and configuration of the filtration apparatus contained in the device. Third, the design of the device makes it difficult to service. Fourth, the design of its air-moving components make it inefficient and noisy. Finally, the device is not aesthetically pleasant because of its bulk and design.
Given the above problems and the disadvantages in existing devices that have been designed to address the problems, there is a need in the art for an air filtration device that is small, efficient, quiet and aesthetically pleasing.
The present invention provides an air filtration device attachable to a motor. The device comprises a housing comprising an upper part and a lower part, wherein the upper and lower parts are parallel and spaced apart from each other and define a cavity therebetween, and wherein the lower part has a centrally positioned opening therein; an impeller positioned coaxially with the axis of the housing between the upper and lower parts thereof and attached to the motor; and a filter positioned between the upper and lower parts and positioned around a perimeter of the housing.